Conventional roll-to-roll lithography systems often use “step and repeat” indexing to bring a substrate with a photosensitive coating or laminate into the exposure area. A mask (also known as a “phototool”) has an image that is typically the full size of the exposure area, and the full area is exposed simultaneously using a broad spectrum ultraviolet and/or visible light source as the substrate is held motionless on vacuum tooling. In order to make long circuits, the circuit must either be fully incorporated within the exposure area or be made from multiple steps or indexes of the exposure cycle. Both of these methods result in processes that make circuits that are longer than the exposure area.
One conventional method to make long circuits is to expose a circuit in a serpentine pattern that fits within the exposure area. This serpentine circuit is subsequently folded into a linear band of conductors. One problem with such a folded circuit design is the resulting periodic thick cross sections that reduce the number of conductive traces capable of being included into a catheter or other device.
A second conventional method to make long circuits involves a multi-step approach wherein multiple mask-derived images representing portions of the long circuit may be joined together. Such long circuits are the result of multiple step exposures, which can result in misalignment error. Such misalignment typically causes narrow bands in conductive traces thereby creating hotspots or fusible links in the circuit.